The present invention relates to a string protector for a racket frame, and more particularly relates to improvement in impact damping of a racket frame used for tennis or the like.
A racket frame such as a tennis racket frame has a general construction in which a head connected to a handle has a substantially oval shape defining a face formed by a latticework of strings held in tension on the head. The head includes a frame top, a pair of lateral zones and a yoke forming a joint of the pair of lateral zones. The head is provided with the first group of through holes which extend substantially parallel to the longer axis of the oval shape and the second group of through holes which extend substantially parallel to the shorter axis of the oval shape. Each string in the latticework is held in tension in the through holes (string holes) in an arrangement such that, on the outer peripheral surface of the head, the string runs in the circumferential direction between adjacent through holes in a same group.
When a ball is shot at the face of a racket frame, impact caused by the shot develops intense vibrations on strings which tend to mar the life of the strings. In an attempt to kill, to say the least to reduce such undesirable vibrations on strings forming the face, a wide variety of string protectors have been proposed in the field.
An attachment-type string protector is one popular example of such conventional proposals. More specifically, such an attachment-type string protector includes a base strap made of a synthetic resin and adapted in shape for attachment to an outer peripheral surface of the yoke forming the proximal part of the head. This base strap is associated with a plurality of sleeves projecting in one body from the planar face of the base strap. The sleeves are aligned along the length of the base strap at positions corresponding to string holes in the yoke. A tubular soft material is tightly inserted into each sleeve and internally provided with one or more annular ribs. The soft material is used for absorption of string vibrations and generally shorter in dimension than the associated sleeve.
In a position attached to the yoke, the sleeve are received in corresponding string holes in the yoke and each string runs through respective sleeves in contact with the inserted soft materials via their annular ribs. In other words, the string is held in position in each sleeve through limited contact with the annular ribs of the associated fort material which is, as stated above, shorter than the sleeve into which it is inserted.
Presence of such a soft material in each sleeve is more or less effective in absorption of string vibrations. However, because of its shorter construction and limited line contact with a string, this attachment-type string protector is rather insufficient in ability of impact damping.